 (def num-birds 30)
 (def avoidance (atom 0.2))
 (def clustering (atom 0.1))
-(def centering (atom 0.01))
+(def centering (atom 0.03))
 
 (def max-acceleration 2)
 

(defn initialize-simulation
  "This is the function where you add everything to the world."
  []
  (let [birds (repeatedly num-birds random-bird)
        floor (make-floor)]
    {:objects (conj birds floor)}))

(start-gui initialize-simulation update-world 0.1)


(defn make-bird
  "Make a new bird with the specified program. At the specified location."
  [position]  
  (make-real {:type :bird
              :color [1 0 0]
              :position position
              :shape (create-box)}))
  
(defn random-bird
  "Make a new random bird."
